Is this a new feature? http://www.google.com/reviews

I don't think I've seen it before, but just became aware of it because it was added to the robots.txt

If you search "google reviews" for the term "2007" sorted by relevance it lists "Spider-man 3 (2007)", but the ratings and reviews seem to actually be based on "Spider-man (2002)" and "Spider" (2002).

"Spider-man (2002)" is a different film.
"Spider (2002)" is an unrelated film.
Note that the above search did not have the term "spider".